1. Field of the Invention
Methods and apparatuses consistent with the exemplary embodiments relate to a method and apparatus for processing and displaying an image signal. More particularly, the exemplary embodiments relate to a method and apparatus for displaying a stereoscopic image. The apparatus is capable of selectively outputting a two-dimensional (2D) or three-dimensional (3D) image, according to a display mode setting signal set by a user.
2. Description of the Related Art
Three-dimensional (3D) images are perceived based on binocular stereopsis. Binocular disparity, i.e., binocular parallax due to the distance between the two eyes which is about 65 mm, is a key factor in providing the perception of stereoscopic depth. When the left and right eyes are presented with different associated images on a two-dimensional (2D) plane, these different images are combined in the brain of the viewer to provide a 3D impression and depth perception.
3D image display technology is generally classified into stereoscopic display, volumetric display, and holographic display. For example, a 3D image display apparatus adopting stereoscopic technology imparts depth information to 2D images, allowing an observer to perceive vividness and reality of three-dimensional images using the depth information.
Systems for 3D viewing can be largely divided into a glasses-type system which requires a pair of eyeglasses, as in FIG. 1A, and a non-glasses-type system which does not require a pair of eyeglasses, as in FIG. 1B. A glasses-type system can provide a visibility range of 120° or more, and the visibility range of a non-glasses-type system is typically 15° or less.
The glasses-type system includes a passive glasses type and an active glasses type. To separately display left-eye and right-eye images, the passive glasses type system may employ eyeglasses having polarizing filters or eyeglasses having blue and red sides for the two eyes respectively. The active glasses type uses liquid crystal shutters for distinguishing between left-eye and right-eye images, wherein viewing via each eye is blocked alternately and chronologically, thereby presenting the left and right eyes with separate images. Thus, in an active glasses-type system, a display apparatus periodically repeats screens that are temporally divided, while a viewer wears a pair of eyeglasses including electronic shutters in synchronization with the period of the display apparatus. The active glass type is also called a time-split type or shuttered glasses type.
As a representative non-glasses-type system, there are a lenticular method and a parallax barrier method. In the lenticular method, a lenticular plate having an array of circular lenses disposed vertically is provided to an image panel. In the parallax barrier method, a barrier layer having regular slits is disposed on an image panel.
Each of the above conventional systems, however, has disadvantages. That is, glasses-type systems require users to wear eyeglasses in order to view stereoscopic images. Non-glasses-type systems, due to their narrow range of visibility, restrict the viewing of stereoscopic images to users situated at a particular position with respect to the display.